Control valves are commonly used in process plants to control the flow of a fluid (e.g., a gas, a liquid, etc.) or any other substance through pipes and/or vessels to which they are connected. A control valve is typically composed of one or more inlets and outlets, and includes a fluid control element or member (e.g., a valve gate, a piston, a valve plug, a control member, etc.) that operates to control fluid flow through apertures that fluidly couple the inlet(s) to the outlet(s). A control member is typically coupled to a valve bonnet that is mechanically coupled (e.g., bolted, clamped, threaded into, etc.) to the valve body. Typically, the control member is configured to engage a sealing structure (e.g., a valve seat) that encompasses a flow path through the valve.
Generally speaking the control elements (including the fluid control member, the seat, and a cage if one exists) are known as “valve trim” or “trim assembly” in the art. In some cases it may be desirable to characterize fluid as it flows through the valve, for example, to reduce pressure. In these cases, a trim assembly may be used that includes a cage with a plurality of openings that are drilled through a wall of the cage. The openings may be sized and shaped to characterize fluid flow as the fluid flows through the openings in the cage, for example by decreasing pressure as the fluid moves through the valve trim. This characterization or pressure reducing process generates unwanted noise.